1. Field of the Invention
This invention relates to diagnosing internal combustion engines electronically.
2. Description of the Prior Art
The diagnosing of internal combustion engines utilizing electronic means has long been known in the art. The most widely used type of diagnostic system relies heavily on display of the actual signals and conditions sensed in the engine for analysis by an operator. Systems more recently put in use tend more toward automatic analysis of the signals and conditions sensed on an engine, with analysis and reduction of the data so as to provide conclusionary results in the form of output signals and/or digital displays indicative of the engine condition and/or suggested repair procedures. The more automated systems, however, cannot perform analytical interpretation of the signals actually sensed, relying solely on the samples taken, and therfore either lose information or must by synchronized with other relevant events in order to take measurements in proper relationship to other events and conditions in the engine. Thus although the automated systems avoid human error, they can instead introduce machine error.
One example of this is found in making electrical measurements (such as of the battery, the starter voltage and the like) during the cranking of the engine by an electrical starting system. In the past, it has been recognized that automated systems, which sample the electrical parameters during cranking, have given less than optical results, the results at times being totally useless in diagnosing conditions which are extant in the engine.